GRAINS-U.S. corn hits 2-week high, soy firm on weather uncertainty

* U.S. corn crop maturing slower than normal

* Soy up on dry Midwest, uncertain path for Hurricane Irma

* Wheat firm in lackluster trade

(New throughout; updates prices, market activity and comments, new byline, changes dateline from previous PARIS/SINGAPORE) CHICAGO, Sept 6 (Reuters) - U.S. corn futures hit a two-week high on Wednesday on a mix of short-covering and worries about the pace of U.S. crop maturity, traders said. Soybeans and wheat futures also posted modest advances. Chicago Board of Trade December corn futures settled up 2-1/2 cents at $3.61 per bushel after reaching $3.62, the highest since Aug. 23. November soybeans ended up 2-1/2 cents at $9.71 a bushel after reaching $9.76-3/4, its highest since Aug. 10. CBOT December wheat rose 2-3/4 cents to $4.45-3/4 a bushel. Corn posted the biggest climb of the three on a percentage basis, buoyed by worries about slow crop maturity that may slow the start of harvest and leave crops vulnerable to bad weather. The U.S. Department of Agriculture in a weekly report late Tuesday said 12 percent of the U.S. corn crop was mature, behind the five-year average of 18 percent. The slow maturity could delay the harvest, which normally begins this month in the Midwest. "Yesterday's crop progress report suggested that corn is going to sit out there for a while. Maturity rates are noticeably behind," said Tom Fritz, analyst with EFG Group. This year's corn crop is unusually variable in terms of yield potential, and high variability typically leads to lower overall yields, research and brokerage firm Linn & Associates said in a note to clients. Forecasts called for cool and mostly dry weather in the U.S. Midwest through next week, potentially stressing soybean crops as they mature. The expected arrival of hurricane Irma in the southeast of the United States next week could also hit some soybean and corn crops, although concerns were more focused on cotton and orange crops. The weather worries helped support futures as traders awaited the USDA's next monthly supply/demand reports on Sept. 12. "Short-covering operations with the approach of the next USDA report and because of dry conditions in the Midwest are offering support to prices," consultancy Agritel said in a note. Additional support stemmed from firm cash markets as U.S. producers slowed cash grain sales, holding out for higher prices. "If you are looking to farmer selling to pressure this thing, that is not going to happen; not at this price," DC Analysis president Dan Cekander said. CBOT wheat firmed in quiet trade but news was lacking. Spring wheat futures on the Minneapolis Grain Exchange jumped 15-1/2 cents at $6.44-1/2 per bushel on bargain buying after a six-week slide.

CBOT settlement prices:

Net Pct Volume

Last change change

CBOT wheat WZ7 445.75 2.75 0.6 59079 CBOT corn CZ7 361.00 2.50 0.7 120210 CBOT soybeans SX7 971.00 2.50 0.3 104309 CBOT soymeal SMZ7 308.70 0.70 0.2 51673 CBOT soyoil BOZ7 35.56 0.12 0.3 51820

NOTE: CBOT September wheat, December corn and November soybeans shown in cents per bushel, December soymeal in dollars per short ton and December soyoil in cents per lb.

(Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; editing by David Clarke and David Gregorio)